ARDMS SPI Study Guide Questions with 100%
Correct Answers
what type of wave is a sound wave?
longitudinal, mechanical
molecules of the medium vibrate at 90 degrees to the direction of the traveling wave
transverse wave
what is the range of audible sound?
20 Hz to 20 kHz
portion of a cycle where the molecules are pushed closer together
compression
portion of a cycle where the molecules spread farther apart
rarefaction
what are the three primary acoustic variables?
pressure, density, particle motion
the time it takes for one cycle to occur
period
the number of cycles per second
frequency
relationship between period and frequency
inverse
,the speed at which sound travels through a medium
propagation speed (c)
relationship between stiffness and propagation speed
direct
"c" of soft tissue
1540 m/s or 1.54 mm/usec
relationship between density, compressibility & elasticity to propagation speed
inverse
length of a single cycle
wavelength
wavelength formula
propagation speed/frequency
max or min deviation of an acoustic variable from the average value of that variable
amplitude
units of pressure amplitude
pascals (Pa)
the rate at which work is performed
power
how are power and amplitude proportioned?
power = amplitude squared
, intensity formula
power/area (w/cm^2)
resistance to the propagation of sound through a medium
impedance (z)
units for impedance
rayls
what causes a strong reflection?
90 degree incidence and strong impedance mismatch
impedance formula
z = density (p) x propagation speed (c)
sound waves are sent into the body and the returning wave is timed to determine the
reflectors distance from the transducer
pulse-echo technique
most common element material
lead zirconate titanate (PZT)
pressure is created when voltage is applied to a material and electricity is created when
pressure is applied to the material
piezoelectric principle
number of pulses produced in 1 second
pulse repetition frequency (kHz)
Correct Answers
what type of wave is a sound wave?
longitudinal, mechanical
molecules of the medium vibrate at 90 degrees to the direction of the traveling wave
transverse wave
what is the range of audible sound?
20 Hz to 20 kHz
portion of a cycle where the molecules are pushed closer together
compression
portion of a cycle where the molecules spread farther apart
rarefaction
what are the three primary acoustic variables?
pressure, density, particle motion
the time it takes for one cycle to occur
period
the number of cycles per second
frequency
relationship between period and frequency
inverse
,the speed at which sound travels through a medium
propagation speed (c)
relationship between stiffness and propagation speed
direct
"c" of soft tissue
1540 m/s or 1.54 mm/usec
relationship between density, compressibility & elasticity to propagation speed
inverse
length of a single cycle
wavelength
wavelength formula
propagation speed/frequency
max or min deviation of an acoustic variable from the average value of that variable
amplitude
units of pressure amplitude
pascals (Pa)
the rate at which work is performed
power
how are power and amplitude proportioned?
power = amplitude squared
, intensity formula
power/area (w/cm^2)
resistance to the propagation of sound through a medium
impedance (z)
units for impedance
rayls
what causes a strong reflection?
90 degree incidence and strong impedance mismatch
impedance formula
z = density (p) x propagation speed (c)
sound waves are sent into the body and the returning wave is timed to determine the
reflectors distance from the transducer
pulse-echo technique
most common element material
lead zirconate titanate (PZT)
pressure is created when voltage is applied to a material and electricity is created when
pressure is applied to the material
piezoelectric principle
number of pulses produced in 1 second
pulse repetition frequency (kHz)
